import streamlit as st
import streamlit.components.v1 as components
import subprocess
import time
import os
import threading
from queue import Queue
import json
import mido

# ------------------------------------------------------------
# Utility Functions
# ------------------------------------------------------------

def install_fluidsynth():
    """
    Check if 'fluidsynth' CLI is installed. Attempt to install if not found.
    On non-Linux systems, you’ll need to manually install fluidsynth. 
    """
    try:
        subprocess.run(['fluidsynth', '--version'], capture_output=True, check=True)
        return True
    except (FileNotFoundError, subprocess.CalledProcessError):
        st.error("FluidSynth not found. Attempting automatic install (Linux only).")
        try:
            subprocess.run(['sudo', 'apt-get', 'update'], check=True)
            subprocess.run(['sudo', 'apt-get', 'install', '-y', 'fluidsynth'], check=True)
            return True
        except subprocess.CalledProcessError as e:
            st.error(f"Failed to install FluidSynth automatically: {str(e)}")
            st.code("Please install fluidsynth manually.")
            return False

def download_soundfont(sf_filename="GeneralUser_GS_v1.471.sf2"):
    """
    Downloads a free SoundFont if it's not already present.
    """
    if not os.path.exists(sf_filename):
        st.info("Downloading soundfont...")
        try:
            subprocess.run([
                'wget', 
                'https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/musicbox/GeneralUser%20GS%20v1.471.sf2',
                '-O', 
                sf_filename
            ], check=True)
        except subprocess.CalledProcessError as e:
            st.error(f"Failed to download soundfont: {str(e)}")
            return False
    return True

# ------------------------------------------------------------
# FluidSynth Handling Class
# ------------------------------------------------------------

class FluidSynthPlayer:
    """
    Wraps the fluidsynth CLI process, sends commands (like note on/off).
    """
    def __init__(self, soundfont_path, gain=2.0, audio_driver='pulseaudio'):
        self.soundfont_path = soundfont_path
        self.process = None
        self.running = False
        self.event_queue = Queue()
        self.gain = str(gain)
        self.audio_driver = audio_driver

    def start(self):
        """Start FluidSynth as a subprocess."""
        try:
            self.process = subprocess.Popen(
                [
                    'fluidsynth',
                    '-a', self.audio_driver,  
                    '-g', self.gain,         
                    self.soundfont_path
                ],
                stdin=subprocess.PIPE,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
                text=True,
                bufsize=1
            )
            self.running = True
            threading.Thread(target=self._process_events, daemon=True).start()
            return True
        except Exception as e:
            st.error(f"Failed to start FluidSynth: {str(e)}")
            return False

    def stop(self):
        """Stop the FluidSynth process."""
        self.running = False
        if self.process:
            self.process.terminate()
            self.process.wait()

    def _process_events(self):
        """Thread to process MIDI events from queue and send to fluidsynth."""
        while self.running:
            try:
                event = self.event_queue.get(timeout=0.1)
                msg_type = event['type']
                if msg_type == 'noteOn':
                    self._send_command(f"noteon 0 {event['note']} {event['velocity']}")
                elif msg_type == 'noteOff':
                    self._send_command(f"noteoff 0 {event['note']}")
            except:
                continue

    def _send_command(self, command):
        """Send a textual command to fluidsynth."""
        if self.process and self.process.poll() is None:
            try:
                self.process.stdin.write(command + '\n')
                self.process.stdin.flush()
            except:
                pass

    def queue_event(self, event):
        """Add a MIDI event to the fluidsynth queue."""
        self.event_queue.put(event)

# ------------------------------------------------------------
# Basic Arpeggiator
# ------------------------------------------------------------

class Arpeggiator:
    """
    A simple arpeggiator that cycles through held notes at a certain speed.
    """
    def __init__(self, synth_player, bpm=120):
        self.synth_player = synth_player
        self.bpm = bpm
        self.notes_held = set()
        self.thread = None
        self.running = False

    def start(self):
        if self.running: